My review follows questions, so you can find the information you need based on your needs.
If you are looking at this magazine, you are probably searching for something with a leftist insight, if not this is not for you. Of course, if you are like many political junkies you may be interested in seeing all sides, this is for you.
What is its political position?
The magazine is far left. If you are looking for something that tilts democrat, I suggest, in order of moderation, The New Republic (more DLC in nature lately) The American Prospect, and The Nation. This magazine has a Green Party, and Libertarian Socialist feel.
What is the difference between the content in the magazine and the stuff on the website?
In brief: a lot. The magazine offers a more journalistic commentary feel on current events and investigations. It covers labor, feminism, environment etc. It feels a lot like In These Times in what it covers. The Website has a lot of leftist academic oriented articles that are posted daily.
Is it worth the subscription?
Yes, except a lot of the stuff is online. I would really check the articles online before you decide to buy it. It will be hard to come by in a library.